This invention relates to the preparation of 1,3-propanediol. In one aspect, the invention relates to a cobalt-catalyzed process for manufacturing 1,3-propanediol in high yields without the use of a phosphine-ligated cobalt catalyst.
1,3-propanediol (PDO) is an intermediate in the production of polyesters for fibers and films. It is known to prepare PDO in a two-step process involving (1) the cobalt-catalyzed hydroformylation (reaction with synthesis gas, H.sub.2 /CO) of ethylene oxide to intermediate 3-hydroxypropanal (HPA) and (2) subsequent hydrogenation of the HPA to PDO. The initial hydroformylation process can be carried out at temperatures greater than 100.degree. C. and at high H.sub.2 /CO pressures to achieve practical reaction rates. The resulting product mixture is, however, rather unselective for HPA.
In an alternate synthesis method, the cobalt catalyst is used in combination with a phosphine ligand to prepare HPA with greater selectivity and at lower temperature and pressure. However, the use of a phosphine ligand adds to the cost of the catalyst and increases the complexity of catalyst recycle.
It would be desirable to prepare HPA in a low temperature, selective process which did not require a phosphine ligand with the cobalt catalyst.
It is therefore an object of the invention to provide an economical process for the preparation of 1,3-propanediol which does not require the use of a phosphine-ligated catalyst for preparation of the HPA intermediate. It is a further object of the invention to provide a process for the preparation of 1,3-propanediol in which essentially all of the cobalt catalyst can be conveniently recycled.